What might account for a soldier experiencing syncope after standing at attention for a long period of time?
Increased respiratory rate.
Vasoconstriction.
Increased heart rate.
Venous pooling.
The Correct Answer is D
Choice D rationale
Venous pooling, particularly in the lower extremities, commonly occurs when standing still for prolonged periods due to the effects of gravity and reduced skeletal muscle pump activity. This pooling decreases venous return to the heart, leading to reduced cardiac output and consequently a drop in cerebral blood flow, which can result in syncope (fainting).
Choice A rationale
Increased respiratory rate (hyperventilation) typically leads to a decrease in carbon dioxide levels, causing respiratory alkalosis. While severe hyperventilation can lead to cerebral vasoconstriction and lightheadedness, it is not the primary physiological mechanism for syncope after prolonged standing.
Choice B rationale
Vasoconstriction, particularly systemic arteriolar vasoconstriction, would generally help maintain blood pressure by increasing total peripheral resistance, counteracting a drop in blood pressure. Therefore, it would typically prevent rather than cause syncope in this scenario, unless it was a compensatory, insufficient response.
Choice C rationale
An increased heart rate is a compensatory mechanism to maintain cardiac output when venous return or stroke volume is reduced, such as during orthostatic stress. While the heart rate does increase, it is often insufficient to prevent the fall in blood pressure that leads to syncope if venous pooling is severe.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A rationale
The visceral layer of the serous pericardium, also known as the epicardium, directly covers the myocardium. Pericardial fluid is not found between these two layers, as they are essentially continuous. The fluid reduces friction between the moving surfaces.
Choice B rationale
The visceral layer of the serous pericardium is the epicardium. Therefore, stating that pericardial fluid is found between the visceral layer and the epicardium is redundant and incorrect, as they represent the same anatomical structure. Pericardial fluid facilitates frictionless movement.
Choice C rationale
Pericardial fluid is a serous fluid found within the pericardial cavity. This cavity is a potential space situated between the parietal layer of the serous pericardium, which lines the fibrous pericardium, and the visceral layer of the serous pericardium (epicardium), which adheres to the heart's surface. This fluid lubricates the heart, allowing it to beat without friction.
Choice D rationale
The myocardium is the muscular layer of the heart wall, and the endocardium is the innermost layer lining the heart chambers. There is no fluid-filled space between the myocardium and endocardium; these layers are contiguous components of the heart wall.
Choice E rationale
The epicardium is the visceral layer of the serous pericardium, and the myocardium is the muscular wall of the heart. These two layers are directly adjacent, with the epicardium forming the outer covering of the myocardium. Pericardial fluid is external to the epicardium.
Correct Answer is B
Explanation
Choice A rationale
The radial artery is a major artery in the forearm, running along the thumb side. It is a common site for pulse palpation and arterial blood gas sampling due to its superficial location. However, it typically terminates by contributing to the deep palmar arch, not forming the superficial palmar arch directly.
Choice B rationale
The superficial palmar arch is a vascular arcade formed primarily by the superficial branch of the ulnar artery, with a contribution from the radial artery. This arch is located just beneath the palmar aponeurosis and gives rise to the common digital arteries, supplying blood to the fingers.
Choice C rationale
Common digital arteries originate from the superficial palmar arch and run distally along the metacarpals. They then bifurcate into proper digital arteries, which supply the individual digits. These are branches of the arch, not the arch itself.
Choice D rationale
The brachial artery is a continuation of the axillary artery and is the main arterial supply to the arm. It typically bifurcates into the radial and ulnar arteries in the cubital fossa, well before reaching the hand to form palmar arches.
Choice E rationale
The ulnar artery is the larger terminal branch of the brachial artery, descending along the medial side of the forearm. Its superficial branch is the primary contributor to the superficial palmar arch, making it a key vessel in the hand's vascular supply.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.